Diffuse Alveolar Septal Amyloid A

A 44-year-old woman became paraplegic following an automobile accident at age 14. Bilateral above the knee amputations were performed at age 20 for chronic osteomyelitis, and a urinary diversion with ileal conduit was performed at age 32. A chronic sacral decubitus ulcer requiring skin grafting developed at age 43. Persistent sepsis with proteus led to her demise. The chest film remained normal throughout. At autopsy, the lung appeared normal.

Sections showed patchy, slight widening of alveolar walls near the pleura and interlobular septa. A homogeneous, pink material in the alveolar walls suggested amyloid. Here, a crystal violet stain shows a violet metachromasia typical of, but not specific for, amyloid.

The material also showed green birefringence after staining with Congo red. The staining and birefringence were abolished after treatment with potassium permanganate, as is characteristic of amyloid A.

At higher magnification, the metachromatic stain appears to follow the distribution of the alveolar-capillary basement membranes along both surfaces of the alveolar wall.

This degree of amyloid deposition is not usually associated with clinical symptoms. In one study of clinical and pathologic correlations, none of five patients with "secondary" amyloid (presumably AA) deposits in the lung was symptomatic, and deposits were small. In contrast, a much higher percentage of patients with AL amyloid in the lung was symptomatic [1].


1.Celli B, Rubinow A, Cohen A, Brody J. Patterns of pulmonary involvement in systemic amyloidosis. Chest 1978; 74:543-547.


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Lugol's Reaction for Amyloid


The slice of heart at the bottom has been treated with Lugol's iodine solution followed by treatment with dilute sulfuric acid. It demonstrates the patchy, marked darkening caused by amyloid--a reaction that was initially described by Virchow. This heart was from an 88-year-old man with intractable heart failure presumably caused by AL. He had no known plasma cell dyscrasia, and a stain for transthyretin was negative. Amyloid fibrils were demonstrated ultrastructurally. There were small amounts of amyloid in vessel walls throughout the body.

The slice of heart at the top shows the untreated myocardium.


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